Is Your Engine Oil Expired? Understanding the Importance of Oil Additives and Maintenance

Dear Mike,

I recently heard someone mention that the oil in my engine can expire over time. Is this true? And if so, why is oil in my engine time sensitive? I always thought as long as I kept up with routine oil changes, I was good to go.

I’m a bit of a car newbie, so any advice you have would be greatly appreciated.



Hey there Cassius,

Thanks for reaching out to me with your question about engine oil. It’s great to hear that you’re taking the time to learn more about your vehicle and maintain it properly.

To answer your question, yes, it’s true that the oil in your engine can expire over time. However, it’s not really the oil itself that expires – it’s the additives that are added to the oil that can get used up and depleted over time.

Let me explain. Motor oil is made up of a base oil and a variety of additives, including acid neutralizers, detergents, and dispersants. The base oil can last for a very long time, but the additives are what do the heavy lifting in protecting your engine. As you drive your car, the additives in the oil start to break down and get used up. Once they’re gone, the oil can no longer do its job properly and it’s time for a change.

Now, when it comes to changing your oil, the best advice I can give you is to refer to your vehicle’s owner’s manual. Each car manufacturer will have different recommendations for oil change intervals based on a variety of factors, including the type of oil used, driving habits, and local climate. Generally speaking, most cars using full synthetic oil can go about 10,000 km between oil changes. However, if you do a lot of stop-and-go driving, drive in extreme temperatures, or drive on dusty roads, you may need to change your oil more frequently.

One thing to keep in mind is that even if you don’t drive a lot, the oil in your engine can still break down over time. This is because the additives can start to break down even if your car is just sitting in the garage. So, even if you only drive your car once a week or less, you should still aim to change your oil on a regular basis – typically once a year is a safe bet.

I hope that helps answer your question, Cassius! Remember, proper oil maintenance is key to keeping your engine running smoothly and preventing costly repairs down the line. If you have any other questions or concerns about your car, feel free to give us a call or drop by our shop – we’re always happy to help!

Mike Urban